CVE-2025-71197

Kernel memory corruption via alarms_store off-by-one copy

Published Feb 4, 2026 · Updated Feb 4, 2026

Heap buffer overflow in the Linux Kernel w1_therm driver allows local users with high privileges to corrupt kernel memory via alarms sysfs writes. alarms_store allocates size bytes for a sysfs buffer whose NUL terminator is at index size, then strcpy copies that terminator one byte past the heap allocation. Reachability requires a loaded w1_therm driver, a supported 1-Wire temperature sensor exposing alarms, and high-privilege local write access; no specific service-failure mode is published.

CVSS severity5.1
Medium
EPSS probability0.20%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap buffer overflow in the Linux Kernel w1_therm driver allows local users with high privileges to corrupt kernel memory via alarms sysfs writes. alarms_store allocates size bytes for a sysfs buffer whose NUL terminator is at index size, then strcpy copies that terminator one byte past the heap allocation. Reachability requires a loaded w1_therm driver, a supported 1-Wire temperature sensor exposing alarms, and high-privilege local write access; no specific service-failure mode is published.

The record

CVE
CVE-2025-71197
Published
Feb 4, 2026
Updated
Feb 4, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Feb 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.8
  2. Affected versionversion=e2c94d6f572079511945e64537eb1218643f2e68 <6a5820ecfa5a76c3d3e154802c8c15f391ef442e
  3. Affected versionversion=e2c94d6f572079511945e64537eb1218643f2e68 <6fd6d2a8e41b7f544a4d26cbd60bedf9c67893a0
  4. Affected versionversion=e2c94d6f572079511945e64537eb1218643f2e68 <761fcf46a1bd797bd32d23f3ea0141ffd437668a
  5. Affected versionversion=e2c94d6f572079511945e64537eb1218643f2e68 <e6b2609af21b5cccc9559339591b8a2cbf884169

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.8; version=e2c94d6f572079511945e64537eb1218643f2e68 <6a5820ecfa5a76c3d3e154802c8c15f391ef442e; version=e2c94d6f572079511945e64537eb1218643f2e68 <6fd6d2a8e41b7f544a4d26cbd60bedf9c67893a0; version=e2c94d6f572079511945e64537eb1218643f2e68 <761fcf46a1bd797bd32d23f3ea0141ffd437668a; version=e2c94d6f572079511945e64537eb1218643f2e68 <e6b2609af21b5cccc9559339591b8a2cbf884169

Published CVSS scores

5.1SUSECVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:N/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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